The classification of ameloblastoma in multicystic or unicystic variants is associated with its clinical behaviour. Recently, BRAF and SMO mutations have been reported in ameloblastomas. However, it is not clear if such mutations are shared by the multi- and unicystic variants of ameloblastoma or by odontogenic carcinomas. We assessed BRAFV600E and SMOF412E in multicystic, unicystic and desmoplastic ameloblastomas. In addition, we investigated whether the BRAFV600E mutation occurs in odontogenic carcinomas. A total of 28 formalin-fixed paraffin-embedded samples, comprising 17 ameloblastomas and 11 odontogenic carcinomas, were included. The BRAFV600E mutation was assessed by real-time PCR with a specific TaqMan probe and confirmed by Sanger sequencing. The SMOF412E mutation was assessed by Sanger sequencing. Fourteen out of 17 (82 %) ameloblastomas showed the BRAFV600E mutation, specifically, 5/6 (83 %) unicystic, 7/9 (78 %) multicystic and 2/2 desmoplastic ameloblastomas. BRAFV600E mutation was detected in 4/11 (36 %) malignant tumours, specifically, 3/8 (38 %) ameloblastic carcinomas and 1/1 clear cell odontogenic carcinoma, while the two ghost cell odontogenic carcinomas did not harbour this mutation. The SMOF412E mutation was not detected in ameloblastoma. The BRAFV600E-activating mutation is a common event in ameloblastomas, occurring regardless of site or histological type. This mutation is also detected in odontogenic carcinomas. SMO somatic mutation is a secondary genetic event in the ameloblastoma pathogenesis. Our findings support the possibility for personalised, molecular-targeted therapy for ameloblastomas and odontogenic carcinomas harbouring the BRAFV600E mutation.

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Oral squamous cell carcinoma (OSCC) is one of the most common malignances. In epithelial-mesenchymal transition (EMT), epithelial cells switch to mesenchymal-like cells exhibiting high mobility. This migratory phenotype is significant during tumor invasion and metastasis. Objective: The aim of this study is to evaluate the expression of the EMT markers E-cadherin, N-cadherin and vimentin in OSCC.Material and Methods : Immunohistochemical detection of E-cadherin, N-cadherin and vimentin was performed on 20 OSCC samples. Differences in the expression of each protein at the invasive front (IF) and in the central/superficial areas (CSA) of the tumor were assessed. Differences in the expression of each protein at the IF of both histologically high- and low-invasive OSCCs were evaluated. Associations among expression of proteins at the IF were assessed. Correlations between the expression levels of each protein at the IF and the tumor stage and clinical nodal status were also evaluated.Results : Reduced expression of E-cadherin was detected in 15 samples (75%). E-cadherin expression was reduced at the IF when compared to the CSA and in high-invasive tumors when compared to low-invasive tumors. All samples were negative for N-cadherin, even though one sample showed an inconspicuous expression. Positive expression of vimentin was observed in 6 samples (30%). Nevertheless, there was no difference in vimentin expression between the IF and the CSA regions or between the low- and high-invasive tumors. Furthermore, no association was observed among protein expression levels at the IF. Finally, no correlations were observed between each protein’s expression levels and tumor stage or clinical nodal status.Conclusions : Reduced E-cadherin expression at the IF and its association with histological invasiveness suggest that this protein is a noteworthy EMT marker in OSCC. Although vimentin was also detected as an EMT marker, its expression was neither limited to the IF nor was it related to histological invasiveness.

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